The present invention relates to machine vision systems and more specifically to a system wherein an aiming pattern can be generated and directed at an area or feature on an object to be imaged to select the feature or object for enhanced analysis.
Machine vision systems have been developed for use in automated inspection systems that capture images of objects within a field of view and examine the objects to determine if the objects have expected features. Where expected features are not present, in some cases the objects are rejected, in other cases an automated process may have to be halted and in still other cases objects have to be reoriented. In early inspection systems object features of interest had to be manually programmed which was complicated and time consuming.
More recent inspection systems have been developed wherein object features of interest are identified during a commissioning procedure wherein an image of an exemplary object to be inspected is obtained and a processor runs a program to identify object features of interest for inspection. In many cases not all image features are of interest for inspection. For instance, in some cases lighting of an object may be such that different portions of a flat or slightly curved surface appear in a captured image to form an edge. Here, the apparent edge is not in fact an edge and typically would not be of interest during object inspection. To help a processor identify features of interest many commissioning procedures require a system user to examine a commissioning image and identify specific image areas or portions that include features of interest that should be identified and trained or learned. Thus, for instance, where two true object edges are adjacent and their relative lengths and juxtapositions are important, the image may be provided on a computer screen and a mouse or other input device may be used to select an area including the two edges after which the training process can commence.
In addition to being usable to specify image areas for training purposes, on-screen images and input devices can also be used to identify different image features for other types of processing. For instance, once an image is captured, a mouse or other input device may be used to select two different points on the image (i.e., points corresponding to image features of interest) for measuring a dimension (e.g., a length, a separation dimension, etc.). Moreover, other features of on screen images can be manually selected for further processing such as specific information marks/symbols (e.g., bar codes) to be decoded, regions of interest that should be searched for known features, etc.
Unfortunately many inspection systems do not include an output device such as a display screen that can be used to examine a commissioning image and to identify portions/areas of the image that include features of interest for training purposes or for identifying features for additional processing.
Thus, it would be advantageous to have a system that allows a user to identify object areas or features for additional processing or training where a display screen and associated input device are not required.
U.S. Pat. No. 6,340,114 teaches a bar code reader that includes an aiming pattern generating device that includes a light source that directs an aiming pattern along a trajectory substantially parallel to the axis of a reader field of view. This patent teaches that two images of a field of view are obtained in rapid succession, one image with the aiming pattern on and the other with the aiming pattern off. Where the field of view is much larger than a bar code to be imaged and decoded, the aiming pattern is placed on the bar code to be read and the two images are obtained. The location of the aiming pattern in the first image is identified and the location information is used to identify an area in the second image in which the bar code should be sought. Here, the aiming device is an integral part of the code reader assembly.
These and other objects and advantages of the invention will be apparent from the description that follows and from the drawings which illustrate embodiments of the invention, and which are incorporated herein by reference.